1. Field of the Invention
This invention relates to a pulse dampener and an associated method and more particularly to an apparatus and method that reduces the effect of pulsations of a liquid flow in a pumping system which includes a reciprocating pump.
2. Background Information
Pulse dampeners are used to absorb pulsations of liquid flow from reciprocating pumps in pumping systems. Known pulse dampeners are constructed with a cover and body separated by an elastic membrane. The body has a cavity which contains a dampening fluid. A temporarily increased feed of fluid results in a pressure rise which is absorbed by the dampening fluid via the elastic partition. If less fluid is conveyed temporarily, the pressure sinks and the damping fluid expands and compensates for the lacking volume.
Pulse dampeners are used extensively in liquid chromatography systems. See, e.g., U.S. Pat. Nos. 4,427,029; 4,629,562; 4,587,993; and 4,548,713. U. S. Pat. No. 4,548,713, for example, discloses a pulse dampener including a body portion having a cavity containing a compliant elastomer medium.
U.S. Pat. No. 4,624,625 discloses a high pressure metering pump including a pulsation damper (FIG. 4). The pulsation damper includes a diaphragm which separates an elastic liquid 67 from the damping volume 61. As pressure of the damping volume 61 increases, liquid 67 is compressed and diaphragm 63 bends towards liquid 67 thus causing an enlargement of damping volume 61. The enlargement, it is said, corresponds to the liquid volume maximally delivered to the pump during one cycle.
Prior art systems, such as those shown, typically operate at high pressures on the order of 1000-3000 psi. These pulse dampeners have been found to be ineffective at lower pressures such as between 0-300 psi.
There is a need for a pulse dampener that is effective in chromatography systems involving lower pressures such as between 0-300 psi.